Maryland governor signs gun control law; NRA vows to sue

Maryland Gov. Martin O'Malley on the opening day of the 2012 legislative… (Patrick Semansky / Associated…)

Maryland has joined the list of states that have toughened gun control in the wake of the December shooting in Newtown, Conn.

Gov. Martin O'Malley on Thursday signed the gun control bill that he promised he would. “We've chosen to take action by advancing the strategies that work to save lives,” he said in a statement.

The new law bans 45 types of assault weapons, decreases the number of bullets allowed in magazines and requires handgun buyers to undergo safety training and submit fingerprints to obtain a license.

Among the assault weapons banned is the AR-15, used in the Newtown massacre, where a lone gunman killed 20 children and six adults before killing himself. Earlier, the gunman, Adam Lanza, killed his mother, with whom he lived.

Maryland joins Connecticut and New York in expanding the ban on assault weapons and other measures. Colorado, where a gunman killed 12 and wounded dozens in a movie theater, has also approved tougher gun controls.

The National Rifle Assn., the leading gun rights advocacy group, has already announced it will seek a legal challenge to the Maryland law. Some residents have promised a petition drive to prevent the law from going into effect.